Network Security and Firewall Configuration

• Firewall Configuration

Firewall Configuration

Installing and configuring UFW (Uncomplicated Firewall)

Add sudo in front of the commands if you are using a normal account with sudo privileges

Installing UFW

1. Use the command below to ensure that UFW is installed

apt-get install ufw

Setting up default policies

1. Use the commands the below to set/reset the firewall policies to default

ufw default deny incoming
ufw default allow outgoing

These commands set the defaults to deny incoming and allow outgoing connections

Allowing SSH connections

1. Allow SSH connections with the following command

ufw allow ssh

Enabling UFW

1. To enable UFW, use this command

ufw enable

You will receive a warning that says the command may disrupt existing SSH connections. We already set up a firewall rule that allows SSH connections, so it should be fine to continue. Respond to the prompt with y

Allowing other connections (examples)

Specific services

ufw allow http

Specific ports

ufw allow 80

Port ranges

ufw allow 6000:6007/tcp
ufw allow 6000:6007/udp

Denying connections

Denying services
================

ufw deny http

Denying a port
============

ufw deny 80

Checking UFW Status and Rules

ufw status verbose

The output should look similar to

Status: active
Logging: on (low)
Default: deny (incoming), allow (outgoing), disabled (routed)
New profiles: skip

To                         Action      From
--                         ------      ----
22/tcp                     ALLOW IN    Anywhere